Since third generation mobile communication was developed, orthogonal frequency division multiplexing (OFDM) has been highlighted from among various multiple access methods. Particularly, the OFDM scheme has been positioned as the next generation mobile communication system in the wireless LAN for transmitting data at a high rate for low mobility, and the WiMAX and 3GPP long term evolution (LTE) that is one of the mobile communication skills having acquired mobility as well as the digital broadcasting.
Hereinafter, an OFDM downlink channel will be briefly described by exemplifying the OFDM used in the 3GPP LTE frequency division duplex (FDD) downlink. The downlink OFDM of the 3GPP LTE distinguishes a frequency resource by using subcarriers having a minimum frequency unit, and distinguishes a time resource by using sub-frames having a minimum time unit and including a plurality of OFDM symbols.
For example, a sub-frame for distinguishing the time resource includes 7 OFDM symbols in consideration of a small cell radius in the 3GPP LTE FDD system. In this instance, the 6 OFDM symbols are used as long symbols and the last OFDM symbol is used as a short symbol. However, in the case of considering a large cell radius, a sub-frame includes 6 OFDM symbols that are long symbols.
Common channels of the downlink include a primary synchronization channel (P-SCH) that is used for a mobile station to acquire sub-frame time synchronization, a secondary synchronization channel (S-SCH) that is used to find a cell group and acquire frame synchronization, a secondary broadcasting channel (SBCH) that is used to broadcast variable information of a cell, and a pilot channel (PCH) that is used for the mobile station to identify the cell and that is used to transmit a reference symbol. The channels are to be received from the base station in order for the mobile station to perform initial camping, and efficient resource allocation for the channels controls the mobile station to more easily perform the initial operation.
However, the frequency resource used for a primary broadcasting channel is determined by the 3GPP LTE from among the many channels. That is, the primary broadcasting channel is determined to use 72 subcarriers with reference to the central frequency, and the time resource for transmitting the primary broadcasting channel, the transmission diversity method, and the method for notifying the primary broadcasting channel's transmission diversity are not yet determined.
Particularly, the 3GPP LTE has not yet described the organic relationship between the downlink common channels, and an integrated mobile station process is difficult to describe. Also, regarding the 3GPP LTE standardization process, the usage of a common channel is determined and limited contents for respective channels are determined, but a method for generating the common channel has not yet been described in detail.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.